Sir Thomas Marchant Williams, writing name T. Marchant Williams, (1845 – 27 October 1914) was a Welsh nationalist, lawyer, and author.
Williams was one of the first students of Aberystwyth University and later received a BA from the University of London. He went on to study law and be active in Welsh associations. In early 1900 he was appointed stipendiary magistrate at Merthyr Tydfil.[1][2] Williams founded the paper The Nationalist.[3] Among his works are The Welsh Members of Parliament[4] and poems such as The Cloud.[5] He received a knighthood by 1905.[6]